Cas12h1 is a compact CRISPR-associated nuclease from functionally diverse type V CRISPR-Cas effectors and recognizes a purine-rich protospacer adjacent motif(PAM)distinct from that of other type V Cas effectors.Here,w...Cas12h1 is a compact CRISPR-associated nuclease from functionally diverse type V CRISPR-Cas effectors and recognizes a purine-rich protospacer adjacent motif(PAM)distinct from that of other type V Cas effectors.Here,we report the nickase preference of Cas12h1,which predominantly cleaves the nontarget strand(NTS)of a double-stranded DNA(dsDNA)substrate.In addition,Cas12h1 acts as a nickase in human cells.We further determined the cryo-EM structures of Cas12h1 in the surveillance,R-loop formation,and interference states,revealing the molecular mechanisms involved in the crRNA maturation,target recognition,R-loop formation,nuclease activation and target degradation.Cas12h1 notably recognizes a broad 5’-DHR-3’PAM(D is A,G,or T;H is A,C,or T;R is A or G)both in vitro and in human cells.In addition,Cas12h1 utilizes a distinct activation mechanism that the lid motif undergoes a“flexible to stable”transition to expose the catalytic site to the substrate.A high-fidelity nucleic acid detector,Cas12h1hf,was developed through rational engineering,which distinguishes single-base mismatches and retains comparable on-target activities.Our results shed light on the molecular mechanisms underlying Cas12h1 nickase,improve the understanding of type V Cas effectors,and expand the CRISPR toolbox for genome editing and molecular diagnosis.展开更多
CRISPR(clustered regularly interspaced short palindromic repeats)-Cas systems,fundamental to prokaryotic adaptive immunity,are divided into two major classes based on their effector protein composition.Class 1 systems...CRISPR(clustered regularly interspaced short palindromic repeats)-Cas systems,fundamental to prokaryotic adaptive immunity,are divided into two major classes based on their effector protein composition.Class 1 systems,including typesⅠ,Ⅲ,andⅣ,utilize multi-subunit complexes to carry out interference(Wang et al.,2022).展开更多
1.Introduction Polyethylene terephthalate(PET)is a thermoplastic resin with excellent optical transparency,gas barrier and mechanical properties,widely used in fibers,plastics and film[1-3].However,PET has a long degr...1.Introduction Polyethylene terephthalate(PET)is a thermoplastic resin with excellent optical transparency,gas barrier and mechanical properties,widely used in fibers,plastics and film[1-3].However,PET has a long degradation half-life in the natural environment,and greenhouse gases such as carbon dioxide will be produced after incineration,indicating that recycling is an effective way to reduce plastic pollution and save energy,and how to correctly use recycled PET(rPET)has become a global concern[4-7].It was reported that each 0.45 kg recycled PET sheet used can reduce energy consumption by 84%and greenhouse gas emissions by 71%compared with the original PET production[8,9].展开更多
The CRISPR-Cas system,an adaptive immunity system in prokaryotes designed to combat phages and foreign nucleic acids,has evolved into a groundbreaking technology enabling gene knockout,large-scale gene insertion,base ...The CRISPR-Cas system,an adaptive immunity system in prokaryotes designed to combat phages and foreign nucleic acids,has evolved into a groundbreaking technology enabling gene knockout,large-scale gene insertion,base editing,and nucleic acid detection.Despite its transformative impact,the conventional CRISPR-Cas effectors face a significant hurdle—their size poses challenges in effective delivery into organisms and cells.Recognizing this limitation,the imperative arises for the development of compact and miniature gene editors to propel advancements in gene-editing-related therapies.Two strategies were accepted to develop compact genome editors:harnessing OMEGA(Obligate Mobile Element-guided Activity)systems,or engineering the existing CRISPR-Cas system.In this review,we focus on the advances in miniature genome editors based on both of these strategies.The objective is to unveil unprecedented opportunities in genome editing by embracing smaller,yet highly efficient genome editors,promising a future characterized by enhanced precision and adaptability in the genetic interventions.展开更多
The adaptive survival mechanisms of bacterial pathogens under host-induced stress are crucial for understanding pathogenesis.Recently,Uppalapati et al.revealed a unique dual function of the Gifsy-1 prophage terminase ...The adaptive survival mechanisms of bacterial pathogens under host-induced stress are crucial for understanding pathogenesis.Recently,Uppalapati et al.revealed a unique dual function of the Gifsy-1 prophage terminase in Salmonella enterica:it acts as a transfer ribonuclease(tRNase)under oxidative stress.The Gifsy-1 prophage terminase targets and fragments tRNALeu to halt translation and temporarily impairs bacterial growth when exposed to high levels of ROS generated by the host immune cells.This response not only preserves genomic integrity by facilitating DNA repair but also inhibits prophage mobilization,thereby aiding in bacterial survival within vertebrate hosts.This study highlights a novel intersection between phage biology and bacterial adaptive strategies.展开更多
Type I CRISPR-Cas systems are the most prevalent and versatile among CRISPR-Cas systems,widely distributed across prokaryotes1.These systems are composed of multisubunit complexes,known as Cascade(CRISPR-associated co...Type I CRISPR-Cas systems are the most prevalent and versatile among CRISPR-Cas systems,widely distributed across prokaryotes1.These systems are composed of multisubunit complexes,known as Cascade(CRISPR-associated complex for antiviral defense),which function by binding to CRISPR RNAs(crRNAs)and targeting complementary DNA sequences for degradation.展开更多
基金supported by the National Key Research and Development Program of China(2021YFC2301403)National Natural Science Foundation of China grants(82225028 and 82172287)Natural Science Foundation of Fujian Province of China(2022J01638).
文摘Cas12h1 is a compact CRISPR-associated nuclease from functionally diverse type V CRISPR-Cas effectors and recognizes a purine-rich protospacer adjacent motif(PAM)distinct from that of other type V Cas effectors.Here,we report the nickase preference of Cas12h1,which predominantly cleaves the nontarget strand(NTS)of a double-stranded DNA(dsDNA)substrate.In addition,Cas12h1 acts as a nickase in human cells.We further determined the cryo-EM structures of Cas12h1 in the surveillance,R-loop formation,and interference states,revealing the molecular mechanisms involved in the crRNA maturation,target recognition,R-loop formation,nuclease activation and target degradation.Cas12h1 notably recognizes a broad 5’-DHR-3’PAM(D is A,G,or T;H is A,C,or T;R is A or G)both in vitro and in human cells.In addition,Cas12h1 utilizes a distinct activation mechanism that the lid motif undergoes a“flexible to stable”transition to expose the catalytic site to the substrate.A high-fidelity nucleic acid detector,Cas12h1hf,was developed through rational engineering,which distinguishes single-base mismatches and retains comparable on-target activities.Our results shed light on the molecular mechanisms underlying Cas12h1 nickase,improve the understanding of type V Cas effectors,and expand the CRISPR toolbox for genome editing and molecular diagnosis.
基金National University of Singapore Presidential Young Professorship(PYP):23-0178-A0001Singapore Ministry of Education Tier 1 grant:23-1065-P0001。
文摘CRISPR(clustered regularly interspaced short palindromic repeats)-Cas systems,fundamental to prokaryotic adaptive immunity,are divided into two major classes based on their effector protein composition.Class 1 systems,including typesⅠ,Ⅲ,andⅣ,utilize multi-subunit complexes to carry out interference(Wang et al.,2022).
基金the National Natural Science Foundation of China(21878267)Research Funds of Institute of Zhejiang University-Quzhou(IZQ2021RCZX037,IZQ2022KYZX11)for supporting this research.
文摘1.Introduction Polyethylene terephthalate(PET)is a thermoplastic resin with excellent optical transparency,gas barrier and mechanical properties,widely used in fibers,plastics and film[1-3].However,PET has a long degradation half-life in the natural environment,and greenhouse gases such as carbon dioxide will be produced after incineration,indicating that recycling is an effective way to reduce plastic pollution and save energy,and how to correctly use recycled PET(rPET)has become a global concern[4-7].It was reported that each 0.45 kg recycled PET sheet used can reduce energy consumption by 84%and greenhouse gas emissions by 71%compared with the original PET production[8,9].
文摘The CRISPR-Cas system,an adaptive immunity system in prokaryotes designed to combat phages and foreign nucleic acids,has evolved into a groundbreaking technology enabling gene knockout,large-scale gene insertion,base editing,and nucleic acid detection.Despite its transformative impact,the conventional CRISPR-Cas effectors face a significant hurdle—their size poses challenges in effective delivery into organisms and cells.Recognizing this limitation,the imperative arises for the development of compact and miniature gene editors to propel advancements in gene-editing-related therapies.Two strategies were accepted to develop compact genome editors:harnessing OMEGA(Obligate Mobile Element-guided Activity)systems,or engineering the existing CRISPR-Cas system.In this review,we focus on the advances in miniature genome editors based on both of these strategies.The objective is to unveil unprecedented opportunities in genome editing by embracing smaller,yet highly efficient genome editors,promising a future characterized by enhanced precision and adaptability in the genetic interventions.
文摘The adaptive survival mechanisms of bacterial pathogens under host-induced stress are crucial for understanding pathogenesis.Recently,Uppalapati et al.revealed a unique dual function of the Gifsy-1 prophage terminase in Salmonella enterica:it acts as a transfer ribonuclease(tRNase)under oxidative stress.The Gifsy-1 prophage terminase targets and fragments tRNALeu to halt translation and temporarily impairs bacterial growth when exposed to high levels of ROS generated by the host immune cells.This response not only preserves genomic integrity by facilitating DNA repair but also inhibits prophage mobilization,thereby aiding in bacterial survival within vertebrate hosts.This study highlights a novel intersection between phage biology and bacterial adaptive strategies.
文摘Type I CRISPR-Cas systems are the most prevalent and versatile among CRISPR-Cas systems,widely distributed across prokaryotes1.These systems are composed of multisubunit complexes,known as Cascade(CRISPR-associated complex for antiviral defense),which function by binding to CRISPR RNAs(crRNAs)and targeting complementary DNA sequences for degradation.
